Hepatocellular carcinomas are highly vascular tumors, showing progressive hypervascularity by the process of neoangiogenesis. Tumor angiogenesis is critical for tumor growth as well as metastatic spread therefore, imaging and quantification of tumor neo-angiogenesis is essential for monitoring response to targeted therapies and predicting disease progression. Sorafenib is a molecular targeting agent used for treating hypervascular tumors. This drug is now the standard of care in treatment of patients with advanced hepatocellular carcinoma. Due to its anti-angiogenic and anti-proliferative actions, imaging findings following treatment with Sorafenib are quite distinct when compared to conventional chemotherapeutic agents. Liver MRI is a widely adopted imaging modality for assessing treatment response in hepatocellular carcinoma and imaging features may reflect pathophysiological changes within the tumor. In this mini-review, we will discuss MRI findings after Sorafenib treatment in hepatocellular carcinoma and review the feasibility of MRI as an early biomarker in differentiating responders from non-responders after treatment with molecular targeting agents.
Aged ; Antineoplastic Agents/*therapeutic use ; Carcinoma, Hepatocellular/drug therapy/physiopathology/*radiography ; Female ; Humans ; Liver Neoplasms/drug therapy/physiopathology/*radiography ; *Magnetic Resonance Imaging ; Male ; Middle Aged ; Niacinamide/*analogs & derivatives/therapeutic use ; Phenylurea Compounds/*therapeutic use ; Tomography, X-Ray Computed

OBJECTIVE: We wanted to investigate the prevalence and causative factors of extrahepatic arterial blood supply to hepatocellular carcinoma (HCC) at its initial presentation and during chemoembolization. MATERIALS AND METHODS: Between February 1998 and April 2000, consecutive 479 patients with newly diagnosed HCC were prospectively enrolled into this study. A total of 1629 sessions of transcatheter arterial chemoembolization (TACE) were performed in these patients (range: 1-15 sessions; mean: 3.4 sessions) until April 2004. For each TACE procedure, we determined the potential extrahepatic collateral arteries (ExCAs) depending on the location of the tumor, and we performed selective angiography of all suspected collaterals that could supply the tumor. The prevalence of ExCAs and the causative factors were analyzed. RESULTS: At initial presentation, 82 (17%) of these 479 patients showed 108 ExCAs supplying tumors. Univariate analysis showed that tumor size (p < 0.01), patient age (p = 0.02), a surface location (p < 0.01), and a bare area location (p < 0.01) were significantly associated with the presence of ExCAs. Multiple logistic regression analysis showed that only tumor size was predictive of ExCA formation (p < 0.01, odds ratio = 1.737, confidence interval: 1.533 to 1.969). During repeated TACE sessions, 97 additional ExCAs were detected in 70 (14%) patients. The cumulative probability of ExCAs in patients with a large tumor (> or = 5 cm) was significantly higher than that for those patients with a small tumor (< 5 cm) (p < 0.01). CONCLUSION: The presence of ExCAs supplying HCC is rather common, and the tumor size is a significant causative factor for the development of these collateral arteries.
Neovascularization, Pathologic/*etiology/physiopathology/radiography ; Middle Aged ; Male ; Logistic Models ; Liver Neoplasms/physiopathology/*therapy ; Humans ; Female ; Collateral Circulation/drug effects/physiology ; Chemoembolization, Therapeutic/*methods ; Carcinoma, Hepatocellular/physiopathology/*therapy ; Angiography ; Aged, 80 and over ; Aged ; Adult